Thienamycin derivatives which are carbapenem antibiotics have excellent antibacterial activity, but they have poor chemical stability and tend to lose their activity due to decomposition by dehydropeptidase I, which is an enzyme present in the human body, and exhibit a low recovery rate in urine [in H. Kropp et al., Antimicrob. Agents Chemother., 22, 62 (1982); S. R. Norrby et al., ibid., 23, 300 (1983)]. In addition, they happen to exhibit nephrotoxicity in some kinds of experimental animals. Among the thienamycin derivatives, imipenem has been used as a mixture with cilastatin which is a dehydropeptidase I inhibitor, while panipenem has been put on the market as a mixture with betamipron which is an organic anion transport inhibitor. After that, chemical stability and stability against dehydropeptidase I were found to be improved by introducing a methyl group at the 1-position of the carbapenem skeleton and then a carbapenem derivatives usable as a single active ingredient preparation such as meropenem (U.S. Pat. No. 5,122,604) has been on the market. As 1-methylcarbapenem derivatives such as meropenem have come to be used frequently in the clinical situation, however, resistant strains against it in Pseudomonas aeruginosa and the like have started to be recognized.
There is accordingly an increasing need for agents which exhibit stronger and well-balanced antibacterial activity against a wide range of bacteria, including strains of Pseudomonas aeruginosa which exhibit resistance against meropenem, and are free from nephrotoxicity. In Japanese Patent Application Kokai No. Hei 5-310740, Japanese Patent Application Kokai No. Hei 5-339269, Japanese Patent Application Kokai No. Hei 6-172356 and Japanese Patent Application Kokai No. Hei 6-199860, 1-methylcarbapenem derivatives synthesized for satisfying the above-described need are disclosed.